LED lighting apparatus and control circuit thereof

ABSTRACT

Disclosed is a light emitting diode lighting apparatus capable of improving a power factor and temperature characteristics. The light emitting diode lighting apparatus according to a preferred embodiment of the present invention includes a light source having a plurality of light emitting diode channels and performs a current regulating operation to allow a light source to emit light. The light source uses a current path provided by current regulating to emit light.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an LED lighting apparatus, and moreparticularly, to an LED lighting apparatus capable of improving a powerfactor and temperature characteristics and a control circuit thereof.

2. Description of the Related Art

For energy saving, a lighting technology of using an LED as a lightsource has been continuously developed.

In particular, a high brightness LED has advantages differentiated fromother light sources in terms of various factors, such as energyconsumption, lifespan, light quality, and the like.

However, a lighting apparatus using an LED as a light source may requirea lot of additional circuits due to a characteristic that the LED isdriven by a constant current.

An example developed to solve the above problem may include an AC directtype lighting apparatus.

The AC direct type LED lighting apparatus generates a rectified voltagefrom a commercial AC power supply to drive the LED and immediately usesthe rectified voltage as an input voltage without using an inductor anda capacitor to obtain a good power factor characteristic.

An example of the foregoing AC direct type LED apparatus is disclosed inKorean Patent No. 10-1128680.

However, as the LED lighting apparatus is increasingly spread, thelighting apparatus using an LED as a light source needs to secure lowpower consumption and an improved power factor and to have simplecomponents and a simple structure.

Further, the LED lighting apparatus may be used in various power supplyenvironments. A power supplying environment for building or home may bechanged and a power supplying environment for each area or each countrymay be changed.

That is, the LED lighting apparatus is in the temporarily instable powersupply environment in addition to the foregoing environments.

As described above, the LED lighting apparatus in various environmentsmay be driven with an AC voltage having a level lower than that of an ACvoltage designed to driving a lighting. In this case, the LED lightingapparatus may be difficult to be light-emitted with designedillumination.

Further, when the LED lighting apparatus is operated in the instablepower supply environment, the LED lighting apparatus may be difficult tomaintain the uniform illumination due to the temporary AC voltage dropphenomenon.

Therefore, the LED lighting apparatus according to the related art isdifficult to maintain illumination due to the environmental factors asdescribed above.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in an effort to solvethe problems occurring in the related art, and an object of the presentinvention is to provide an LED lighting apparatus which has an improvedpower factor, provides a current path for allowing a light sourceincluding a plurality of LED channels to emit light by using a currentdetection voltage varying depending on the light-emitting state of thelight source, and has a simple structure.

Another object of the present invention is to provide an LED lightingapparatus capable of performing sequential light-emitting or quenchingfor each of the plurality of LED channels connected to each other inseries or improving current regulation due to light emitting orquenching for each channel.

Still another object of the present invention is to provide an LEDlighting apparatus in which LED channels included in a light source arearranged in a predetermined region so as to have improved heat radiatingefficiency and illumination.

Still another object of the present invention provides an LED lightingapparatus capable of securing uniform illumination by compensating forpower supplied to a lighting light-emitted by driving LEDs to cope withbuilding or local or national power supply environment factors ortemporarily unstable power supply environment factors and a controlcircuit thereof.

In order to achieve the above object, according to one aspect of thepresent invention, there is provided an LED lighting apparatus,including: a power supply unit configured to convert an AC voltage andprovide a rectified voltage; a light source configured to include Nlight emitting diode (LED) channels (N is a natural number) including atleast one LED; and a current control circuit configured to divide avarying width of the rectified voltage into N periods in response tolight-emitting voltages for each LED channel, detect current flowing inthe LED channels corresponding to the period, and control the lightsource to emit light by comparing a current detection voltagecorresponding to the detected current with a reference voltagereflecting the variation of the rectified voltage.

In order to achieve the above object, according to another aspect of thepresent invention, there is provided a control circuit of an LEDlighting apparatus driving a light source including N (N is a naturalnumber) LED channels including at least one LED configured in serieswith a rectified voltage, the control circuit of an LED lightingapparatus including: N switching circuits configured to be connected toeach output terminal of the N LED channels having a light-emittingvoltage defining a varying width of the rectified voltage as N periodsin parallel to form current paths; N current detection resistorsconfigured to be independently connected to the N switching circuits anda ground to provide a current detection voltage; a voltage sensing unitconfigured to sense the variation of the rectified voltage to provide acompensation voltage; and a reference voltage generation circuitconfigured to generate and provide reference voltages having differentlevels for each of the N switching circuits and reflecting thecompensation voltage, wherein the N switching circuits compare their ownreference voltage with the current detection voltage correspondingthereto to selectively provide the current paths.

In order to achieve the above object, according to still another aspectof the present invention, there is provided a control circuit of an LEDlighting apparatus driving a light source including N (N is a naturalnumber) LED channels including at least one LED configured in serieswith a rectified voltage, the control circuit of an LED lightingapparatus including: N switching circuits configured to be connected toeach output terminal of the N LED channels having a light-emittingvoltage defining a varying width of the rectified voltage as N periodsin parallel to form current paths; N current detection resistorsconfigured to be independently connected to the N switching circuits anda ground to provide a current detection voltage; a voltage sensing unitconfigured to sense the variation of the rectified voltage to provide acompensation voltage; and a reference voltage generation circuitconfigured to commonly provide a reference voltage having a fixed leveland reflecting the compensation voltage to each switching circuit,wherein the N switching circuits compare the reference voltage with thecurrent detection voltage corresponding thereto to selectively providethe current paths.

In order to achieve the above object, according to still another aspectof the present invention, there is provided an LED lighting apparatus,including: a power supply unit configured to convert an AC voltage andprovide a rectified voltage; a light source configured to include Nlight emitting diode (LED) channels (N is a natural number) including atleast one LED; and a current control circuit configured to divide avarying width of the rectified voltage into N periods in response tolight-emitting voltages for each LED channel, detect current flowing inthe LED channels corresponding to the period, and control the lightsource to emit light by using a current detection voltage correspondingto the detected current.

In order to achieve the above object, according to still another aspectof the present invention, there is provided a control circuit of an LEDlighting apparatus driving a light source including N (N is a naturalnumber) LED channels including at least one LED configured in serieswith a rectified voltage, the control circuit of an LED lightingapparatus including: N switching circuits configured to be connected toeach output terminal of the N LED channels having a light-emittingvoltage defining a varying width of the rectified voltage as N periodsin parallel to form current paths; N current detection resistorsconfigured to be independently connected to the N switching circuits anda ground to provide a current detection voltage; and a reference voltagegeneration circuit configured to generate and provide reference voltageshaving different levels for each of the N switching circuits, whereinthe N switching circuits compare their own reference voltages with thecurrent detection voltage corresponding thereto to selectively providethe current paths.

In order to achieve the above object, according to still another aspectof the present invention, there is provided a control circuit of an LEDlighting apparatus driving a light source including N (N is a naturalnumber) LED channels including at least one LED configured in serieswith a rectified voltage, the control circuit of an LED lightingapparatus including: N switching circuits configured to be connected toeach output terminal of the N LED channels having a light-emittingvoltage defining a varying width of the rectified voltage as N periodsin parallel to form current paths; N current detection resistorsconfigured to be independently connected to the N switching circuits anda ground to provide a current detection voltage; and a reference voltagegeneration circuit configured to commonly provide a reference voltagehaving a fixed level to each switching circuit, wherein the N switchingcircuits compare the reference voltage with the current detectionvoltage corresponding thereto to selectively provide the current paths.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects, and other features and advantages of the presentinvention will become more apparent after a reading of the followingdetailed description taken in conjunction with the drawings, in which:

FIG. 1 is a circuit diagram illustrating an LED lighting apparatusaccording to a preferred embodiment of the present invention;

FIG. 2 is a waveform diagram illustrating operation characteristics of adriving apparatus of FIG. 1;

FIG. 3 is a layout illustrating a method of arranging LEDs for LEDchannels of a light source;

FIG. 4 is a layout illustrating an example in which the LED channels ofthe light source are arranged on a predetermined region of a substrate;

FIG. 5 is a diagram illustrating an example in which the substrate ofFIG. 4 is divided into three regions;

FIG. 6 is a layout illustrating light-emitting states by the arrangementof FIG. 4;

FIG. 7 is a layout illustrating light-emitting states of LED channels byan arrangement different from FIG. 4;

FIG. 8 is a circuit diagram illustrating an LED lighting apparatusaccording to another preferred embodiment of the present invention;

FIG. 9 is a circuit diagram illustrating an LED lighting apparatusaccording to another preferred embodiment of the present invention;

FIG. 10 is a circuit diagram illustrating an LED lighting apparatusaccording to another preferred embodiment of the present invention,which senses a rectified voltage to compensate for power; and

FIGS. 11 and 12 are circuit diagrams illustrating an LED lightingapparatus according to another preferred embodiment of the presentinvention, which senses a rectified voltage to compensate for power.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings. Termsused in the present specification and claims is not to be construed as ageneral or dictionary meaning and is to be construed as meaning andconcept meeting technical matters of the present invention.

A preferred embodiment disclosed in the present specification and aconfiguration illustrated in the drawings are the preferred embodimentof the present invention and do not represent the all technical mattersof the present invention and therefore various equivalents andmodifications replacing these technical matters at the time of thepresent application may be implemented.

An LED lighting apparatus according to a preferred embodiment of thepresent invention is implemented as an AC direct type.

The preferred embodiment of the present invention discloses aconfiguration of detecting a change in current in response to arectified voltage with a current detection voltage and controllingcurrent paths for each of the plurality (N number, wherein N is anatural number) of LED channels connected to each other in series tocontrol a light source to emit light.

Referring to FIG. 1, a LED lighting apparatus according to a preferredembodiment of the present invention may include a power supply unit, alight source 12, and a current control circuit 14.

The power supply unit converts an AC voltage applied from the outer sideto output a rectified voltage and may include an AC power supply VACwhich supplies an AC voltage and a rectifying circuit 10 which rectifiesthe AC voltage to output the rectified voltage. Herein, the AC powersupply VAC may be a commercial AC power supply.

The rectifying circuit 10 performs a full-wave rectification on an ACvoltage having a sine wave of the AC power supply VAC to output therectified voltage. Therefore, the rectified voltage has a ripplecomponent which increases and decreases a voltage level in a unit of ahalf period of the commercial AC voltage.

The light source 12 includes three LED channels LED1, LED2, and LED3connected to each other in series. The three LED channels LED1, LED2,and LED3 each include at least one LED connected to each other inseries. Further, the three LED channels LED1, LED2, and LED3 may eachinclude the same or different LEDs and a dotted line illustrated in FIG.1 for each LED channel LED1, LED2, and LED3 represents that theillustration of the LEDs are omitted.

The preferred embodiment of the present invention illustrates that thelight source 12 includes the three LED channels LED1, LED2, and LED3 butis not limited thereto, and therefore may be applied to the case inwhich the light source 12 includes a various number of LED channels.

Further, the current control circuit 14 is a current regulating circuitand detects a change in a rectified voltage with the current detectionvoltage so as to provide a current path for regulating a current.Therefore, the current control circuit 14 serves to control the lightsource 12 to emit light in response to the current rectified voltagestate.

The light-emitting of the three LED channels LED1, LED2, and LED3included in the light source 12 is controlled by the current controlcircuit 14.

In more detail, when the rectified voltage rises, the three LED channelsLED1, LED2, and LED3 is configured to be sequentially light-emitted fromone applied with the rectified voltage to another farthest awaytherefrom and the number of light-emitted LED channels increases. Whenthe rectified voltage falls, the three LED channels LED1, LED2, and LED3are sequentially quenched from another farthest away from one appliedwith the rectified voltage and the number of quenched LEDs decreases. Inthis case, the current control circuit 14 forms the current paths in theLED channels corresponding to the current light-emitting voltage state.

As described above, the light-emitting of the light source 12 may becontrolled by the current control circuit 14 and the current controlcircuit 14 may include a reference voltage generation circuit 20, acurrent detection resistor Rg, and three switching circuits 30_1, 30_2,and 30_3.

In this configuration, the reference voltage generation circuit 20includes a plurality of resistors R1, R2, . . . , R4 which are appliedwith a constant voltage Vref and connected to each other in series.

The resistor R1 is connected to a ground and the resistor R4 is appliedwith the constant voltage Vref. The resistor R4 serves as a loadresistor for adjusting an output. The resistors R1, R2, and R3 are tooutput reference voltages VREF1, VREF2, and VREF3 having differentlevels. Among the reference voltages VREF1, VREF2, and VREF3, thereference voltage VREF1 has the lowest voltage level and the referencevoltage VREF3 has the highest voltage level.

That is, as illustrated in FIG. 2, each resistor R1, R2, and R3 may beset to output the three reference voltages VREF1, VREF2, and VREF3having gradually increasing levels in response to the rising of therectified voltage to the three LED channels LED1, LED2, and LED3.

In more detail, the three reference voltages VREF1, VREF2, and VREF3 maybe generated to have levels for forming the current paths forlight-emitting or quenching the three LED channels LED1, LED2, and LED3connected to each of the three switching circuits 30_1, 30_2, and 30_3.

The reference voltage VREF1 has a level to turn off the switchingcircuit 30_1 when the LED channel LED2 is light-emitted. In more detail,the reference voltage VREF1 may be set to a level lower than that of thecurrent detection voltage formed in the current detection resistor Rg bythe light-emitting voltage V2 of the LED channel LED2.

Further, the reference voltage VREF2 has a level to turn off theswitching circuit 30_2 when the LED channel LED3 is light-emitted. Inmore detail, the reference voltage VREF2 may be set to a level lowerthan that of the current detection voltage formed in the currentdetection resistor Rg by a light-emitting voltage V3 of the LED channelLED3.

Further, the reference voltage VREF3 ensures the stable light-emittingof the LED channel LED3 in an upper bound level region of the rectifiedvoltage. The level of the reference voltage VREF3 may be set inconsideration of the turn off of the switching circuit 30_3 in responseto the overvoltage of the rectified voltage. Herein, the upper boundlevel region of the rectified voltage may be defined as a level higherthan that of the light-emitting voltage V3.

Further, the light-emitting voltages V1, V2, and V3 for each of thethree LED channels LED1, LED2, and LED3 may be defined as a voltagerequired for the light-emitting of each channel.

In more detail, the light-emitting voltage V1 of the LED channel LED1may be defined as a level to turn on the LEDs included in the LEDchannel LED1. Further, the light-emitting voltage V2 of the LED channelLED2 may be defined as a level to allow the LEDs included in the LEDchannels LED1 and LED2 to be light-emitted. Further, the light-emittingvoltage V3 of the LED channel LED3 may be defined as a level to turn onthe LEDs included in the three LED channels LED1, LED2, and LED3.

Further, a variable width of the rectified voltage may be divided intothree periods based on the light-emitting voltages V1, V2, and V3 andwhen the rectified voltage enters the above specific period due to therising or falling thereof, the LED channels corresponding to thecorresponding period may be turned on by the operation of thecorresponding switching circuit.

FIG. 2 is a waveform diagram illustrating the case in which the threeLEDs LED1, LED2, and LED3 are driven, which is to illustrate thecorrelation of the rectified voltage, the turn on current, and thelight-emitting voltage.

It can be appreciated from FIG. 2 that the rectified voltage has periodsCH1, CH2, and CH3 divided based on voltage values, that is, thelight-emitting voltages V1, V2, and V3 when the LED channels LED1, LED2,and LED3 are light-emitted and the turn on current having differentlevels for each period CH1, CH2, and CH3 is maintained as a constantcurrent state.

The preferred embodiment of the present invention illustrated in FIGS. 1and 2 illustrates a configuration and an operation of the LED lightingapparatus using the three LED channels, but the LED lighting apparatusmay be configured by increasing the number of LED channels to Naccording to manufacturer's intention. As a result, the channels of FIG.2 may be subdivided, such that the level of the reference voltage may bedesigned to follow up the change in the rectified voltage.

Meanwhile, the three switching circuits 30_1, 30_2, and 30_3 areconnected to each LED channels LED1, LED2, and LED3 in parallel and eachswitching circuit 30_1, 30_2, and 30_3 is connected between grounds tocommonly connect to the current detection resistor Rg providing thecurrent detection voltage.

Further, the three switching circuits 30_1, 30_2, and 30_3 provides asingle current path for allowing the light source 12 to emit light.

The three switching circuits 30_1, 30_2, and 30_3 compare their ownreference voltage with the current detection voltage of the currentdetection resistor Rg and when the current detection voltage meets turnon conditions, are turned on and when the current detection voltagerises beyond the turn on conditions, are turned off.

The three reference voltages VREF1, VREF2, and VREF3 have the increasedlevel in the switching circuits 30_1, 30_2, and 30_3 connected to theLED channels LED1, LED2, and LED3 which are far away from a position towhich the rectified voltage is applied. In other words, when the numberof LED channels included in the light source is N, the level of thereference voltage applied to the switching circuit corresponding to anN-th LED channel is higher than that of the reference voltage applied tothe switching circuit corresponding to an N-1-th LED channel.

Each switching circuit 30_1, 30_2, and 30_3 includes comparators 50which compare the reference voltage corresponding thereto with thecurrent detection voltage applied to the current detection resistor Rgand switching elements which turn on/off the current paths between theLED channels connected thereto and the current detection resistor Rg byoutputs of the comparators 50. In this configuration, the switchingelement may be configured of an NMOS transistor 52.

Negative (−) terminals of the comparators 50 of each switching circuit30_1, 30_2, and 30_3 are commonly connected to the current detectionresistor Rg so as to apply the current detection voltage.

Positive (+) terminals of the comparators 50 of each switching circuit30_1, 30_2, and 30_3 are configured to be applied with the correspondingreference voltages VREF1, VREF2, and VREF3 which are applied from thereference voltage generation circuit 14.

NMOS transistors 52 of each switching circuit 30_1, 30_2, and 30_3 areconfigured to have sources connected to output terminals of thecorresponding LED channels LED1, LED2, and LED3, respectively, gatesconnected to output terminals of the comparators 50, and drains commonlyconnected to the negative (−) terminals of the comparators and thecurrent detection resistor Rg.

By the above configuration, each switching circuit 30_1, 30_2, and 30_3compares the reference voltages VREF1, VREF2, and VREF3 correspondingthereto with the current detection voltage of the current detectionresistor Rg and when the compared results meet the turn on conditions,is turned on.

That is, in each switching circuit 30_1, 30_2, and 30_3, the comparators50 compare the reference voltage corresponding thereto with thedetection voltage of the current detection resistor Rg and when thecompared results meet the turn on conditions, outputs a signal having alevel to turn on the NMOS transistor 52, such that the NMOS transistors52 may be turned on according to the outputs of the comparators 50.

The current detection resistor Rg is applied with the current from theturned on switching circuit and the current detection voltage of thecurrent detection resistor Rg has an increasing level as a currentinflow amount increases in response to the rising of the rectifiedcurrent and a decreasing level as a current inflow amount decreases inresponse to the falling of the rectified voltage.

A detailed operation of the preferred embodiment of the presentinvention configured as illustrated in FIG. 1 will be described.

The preferred embodiment of the present invention controls the currentregulating and the formation of the current path to control thelight-emitting of the LED channel.

When the rectified voltage is in an initial state, the LED channels arenot light-emitted. Further, the current detection resistor Rg provides alow-level current detection voltage. Herein, the initial state of therectified voltage may be defined as a state in which the level of therectified voltage is lower than that of the light-emitting voltage V1light emitting the LED channel LED1.

When the rectified voltage is in an initial state, all the switchingcircuit 30_1, 30_2, and 30_3 maintains the turned on state since thereference voltages VREF1, VREF2, and VREF3 applied to positive (+) inputterminals is higher than that of the current detection voltage appliedto negative (−) input terminals.

Even though all the switching circuits 30_1, 30_2, and 30_3 areinitially maintained in the turned on state, when the rectified voltagedoes not reach the light-emitting voltage V1 to allow the LED channelLED1 to be light-emitted, the light source 12 does not emit light andthe current path is not also formed.

When the rectified voltage rises to reach the light-emitting voltage V1to allow the LED channel LED1 to be light-emitted, the turned onswitching circuit 30_1 of the current control circuit 14 connected tothe LED channel LED1 provides the current path and the LED channel LED1is light-emitted. As described above, when the rectified voltage reachesthe light-emitting voltage V1 to allow the LED channel LED1 to belight-emitted, the level of the current detection voltage of the currentdetection resistor Rg increases due to the flow of current through theswitching circuit 30_1 providing the current path. In this case,however, since the level of the current detection voltage is low, theturned on state of the switching circuits 30_1, 30_2, and 30_3 is notchanged.

Thereafter, the rectified voltage continuously rises, and thus thecurrent of the output terminal of the LED channel LED1 increases andwhen the switching circuit 30_1 exceeds a threshold value of a currentamount maintaining the turned on state, the current detection voltage ofthe current detection resistor Rg rises, and thus the switching circuit30_1 is turned off. In this case, the voltage of the input terminal ofthe LED channel LED2 reaches the light-emitting voltage V2, the LEDchannel LED2 is light-emitted, and the current path for light-emittingthe LED channel LED2 is formed by the turned on switching circuit 30_2.

In this case, the LED channel LED1 also maintains the light-emittingstate.

The turn off of the switching circuit 30_1 is due to the increase in thelevel of the current detection voltage of the current detection resistorRg. That is, as described above, when the rectified voltage reaches thelight-emitting voltage V2 to allow the LED channel LED2 to belight-emitted, the level of the current detection voltage of the currentdetection resistor Rg increases due to the flow of current through theswitching circuit 30_2 providing the current path. In this case, thelevel of the current detection voltage is higher than that of thereference voltage VREF1. Therefore, the NMOS transistor 52 of theswitching circuit 30_1 is turned off by the output of the comparator 50.That is, the switching circuit 30_1 is turned off and the switchingcircuit 30_2 provides the selective current path corresponding to thelight-emitting of the LED channel LED2.

Thereafter, the rectified voltage continuously rises, and thus thecurrent of the output terminal of the LED channel LED2 increases andwhen the switching circuit 30_2 exceeds a threshold value of a currentamount maintaining the turned on state, the current detection voltage ofthe current detection resistor Rg rises, and thus the switching circuit30_2 is turned off. In this case, the voltage of the input terminal ofthe LED channel LED3 reaches the light-emitting voltage V3, the LEDchannel LED3 is light-emitted, and the current path for light-emittingthe LED channel LED3 is formed by the turned on switching circuit 30_3.

In this case, the LED channels LED1 and LED2 also maintain thelight-emitting state.

The turn off of the switching circuit 30_2 is due to the increase in thelevel of the current detection voltage of the current detection resistorRg. That is, as described above, when the rectified voltage reaches thelight-emitting voltage V3 to allow the LED channel LED3 to belight-emitted, the level of the current detection voltage of the currentdetection resistor Rg increases due to the flow of current through theswitching circuit 30_3. In this case, the level of the current detectionvoltage is higher than that of the reference voltage VREF1. Therefore,the NMOS transistor 52 of the switching circuit 30_1 is turned off bythe output of the comparator 50. That is, the switching circuit 30_1 isturned off and the switching circuit 30_2 provides the selective currentpath corresponding to the light-emitting of the LED channel LED2.

Thereafter, even though the rectified voltage continuously rises, thereference voltage VREF3 provided to the switching circuit 30_3 has alevel higher than that of the current detection voltage formed in thecurrent detection resistor Rg by the upper bound level of the rectifiedvoltage, such that the switching circuit 30_3 may maintain the turned onstate.

As described above, when the LED channels LED1, LED2, and LED3 aresequentially light-emitted in response to the rising of the rectifiedvoltage, the turn on current corresponding to the light-emitting stateincreases gradually as illustrated in FIG. 2. That is, since the currentcontrol circuit 14 performs the constant current regulating operation,current corresponding to the light-emitting for each LED channelmaintains a constant level and when the number of light-emitted LEDchannels increases, the current level increases accordingly.

As described above, the rectified voltage rises to the upper bound leveland starts to fall.

When the rectified voltage starts to decrease from the upper bound leveland decreases to a light-emitting voltage VCH3 or smaller, the LEDchannel LED3 is hard to maintain the light-emitting. In this case, theswitching circuit 30_2 is turned on by the falling of the currentdetection voltage of the current detection resistor Rg. Therefore, theLED channel LED3 is quenched and the light-emitting thereof ismaintained by the LED channels LED2 and LED1. The current path forlight-emitting the LED channels LED2 and LED1 is provided by the turnedon switching circuit 30_2. Thereafter, when the rectified voltagesequentially falls to the light-emitting voltage V2 and thelight-emitting voltage V1 or less by the falling of the rectifiedvoltage, the LED channels LED2 and LED1 of a lighting 10 aresequentially quenched.

The current control circuit 14 shifts the selective current path formedby the switching circuits 30_3, 30-2, and 30_1 in response to thesequential quenching of the LED channels LED3, LED2, and LED1 of thelighting 10. Further, the level of the turn on current also decreasesgradually in response to the quenching state of the LED channels LED3,LED 2, and LED1.

As described above, the preferred embodiment of the present inventionmay sequentially perform the light-emitting and quenching of the LEDchannels in response to the rising and falling of the rectified voltageand control the current regulating and the current path formation inresponse to the light-emitting and quenching of the LED channels.

As described above, according to the preferred embodiment of the presentinvention, the LED channels LED1, LED2, and LED3 may be sequentiallylight-emitted or quenched in response to the variation of the currentdetection voltage and the rising and falling of the rectified voltagedue to a current flowing in the single current detection resistor Rg.That is, the LED channels LED1, LED2, and LED3 may be additionallyturned on one by one to a position far away from a position at which therectified voltage is applied and may be additionally turned off one byone in an opposite direction thereto.

Therefore, the preferred embodiment of the present invention does notuse an inductor, a capacitor, and the like as well as applies thecurrent detection voltage in proportion to the rectified voltage to eachchannel, thereby securing the optimal power factor and securing thesufficient current regulating characteristics.

Further, the preferred embodiment of the present invention uses thesingle current detection resistor to form the current paths for each LEDchannel to simplify components configuring the LED driving circuit, suchthat the circuit may be implemented to have a simple structure.

Meanwhile, the preferred embodiment of the present invention improvesthe aligned state of the LED channels included in the light source 12,which is arranged in a predetermined region on the substrate, therebyimproving heat radiating efficiency and illumination.

According to the preferred embodiment of the present invention, asillustrated in FIG. 3A, the LEDs for the three LED channels included inthe light source 12 may be arranged at a uniform distance D.

Unlike this, according to the preferred embodiment of the presentinvention, as illustrated in FIG. 3B, the LEDs may be arranged at adifferent distances D1>D2>D3 for each of the three LED channels includedin the light source 12.

Further, the three LED channels arranged as illustrated in FIGS. 3A and3B may be arranged in a helical form in within a predetermined region ona plane substrate 100.

As can be appreciated from the description of FIGS. 1 and 2, since theLED channel LED1 firstly connected to the power supply apparatusmaintains the light-emitting state for the longest time, the LED channelLED1 generates the most heat Further, since the LED channel LED3 finallyconnected to the power supply apparatus has the reduced time tosequentially maintain the light-emitting state and the reduced heatvalue, the LED channel LED3 maintains the light-emitting state for theshortest time and generates the smallest heat.

In the above description, since the LED channel LED1 light-emitted forthe longest time most needs heat radiating, the LED channel LED1 has thehigher heat radiating priority and since the LED channel LED3maintaining the light-emitting state for the shortest time generates thesmallest heat, the LED channel LED3 has the lower heat radiatingpriority.

Therefore, as illustrated in FIG. 4, when N LED channels are arranged ina helical form on the plane substrate 100, according to the preferredembodiment of the present invention, the LED channel LED1 firstlyconnected to the power supply apparatus to have the higher heatradiating priority generating the most heat is arranged at the outerside and the LED channels sequentially connected thereto may beconfigured to be gradually arranged in the inner side.

In more detail, according to the preferred embodiment of the presentinvention, when the light source 12 includes the three LED channelsLED1, LED2, and LED3, as illustrated in FIGS. 4 and 6A to 6C, the LEDchannel LED1 firstly connected to the power supply apparatus is arrangedat the outermost side A1 of FIG. 5, and then the LED channels LED2 andLED3 connected thereto in order may be gradually arranged in a region A3between the outermost side A1 and the center A2 and at a center A2.

Therefore, the LED channels LED1, LED2, and LED3 included in the lightsource 12 may be light-emitted in an order of FIGS. 6A to 6C in responseto the rising of the rectified voltage.

According to the preferred embodiment of the present inventionconfigured as illustrated in FIGS. 4 and 6A to 6C, the LED channelhaving a large heat value due to the long light-emitting time isarranged at the outer side, such that the heat radiating space may besecured. Therefore, the heat radiating efficiency of the lightingapparatus may be improved.

For implementing the more efficient heat radiating, the LED channelsLED1, LED2, and LED3 illustrated in FIGS. 4 and 6A to 6C may be arrangedso that a spacing between the LEDs included in the LED channel locatedat the outer side may be arranged to be gradually wider than a spacingof the LEDs included in the LED channel located in the inner sideillustrated in FIG. 3B.

Further, according to the preferred embodiment of the present invention,the LED channels LED1, LED2, and LED3 as illustrated in FIGS. 7A to 7Cmay be arranged.

FIGS. 7A to 7C illustrate that the LED channel LED1 firstly connected tothe power supply apparatus is arranged at the outermost side A1 of FIG.5, the LED channel LED2 secondly connected thereto is arranged at thecenter A2 of FIG. 5, and the LED channel LED3 finally connected theretois arranged in the region A3 between the outermost side A1 and thecenter A2 of FIG. 5.

Therefore, according to the preferred embodiment of FIG. 7, the LEDchannel LED1 at the outermost A1 is light-emitted in response to therising of the rectified voltage, the LED channel LED2 at the center A2is light-emitted, and finally, the LED channel LED3 in the region A3between the outermost side A1 and the center A2 is light-emitted.

According to the preferred embodiment of FIG. 7, as the LED channel LED3having the short light-emitting time is arranged in the region A3between the outermost side A1 and the center A2, the heat radiatingspace between the LED channel LED1 having the largest heat value and theLED channel LED2 having the second largest heat value during thequenching of the LED channel LED3 may be secured.

Further, according to the preferred embodiment of the present invention,as the light-emitting is progressed to the outermost side A1, the centerA2, and the region A3 therebetween, the light-emitting state may bedispersed, thereby improving the front illumination of the lightingapparatus.

In configuring the preferred embodiment of FIG. 7, when it is difficultto connect the LED channel LED1 to the LED channel LED3 in a twodimension, the electrical connection between respective channels may beimplemented by using a connection member, such as a jumper. In thiscase, each LED channel LED1, LED2, and LED3 may have a pattern in whichwirings for each channel are disconnected in a two dimension.

Meanwhile, the preferred embodiment of the present invention may beperformed by a configuration adopting independent current detectionresistors for each of the three LED channels LED1, LED2, and LED3 asillustrated in FIG. 8.

The preferred embodiment of FIG. 8 is different from the preferredembodiment of FIG. 1 in terms of the configuration of current detectionresistors Rg1, Rg2, and Rg3 independently connected to each switchingcircuit 30_1, 30_2, and 30_3, instead of the configuration of thecurrent detection resistor Rg, but the remaining components of thepreferred embodiment of FIG. 8 are the same as those of the preferredembodiment of FIG. 1, and therefore the configuration and operation ofthe components will not be repeatedly described.

In the configuration of FIG. 8, the three current detection resistorsRg1, Rg2, and Rg3 may have uniform resistance values so as to satisfythe turn on conditions for each of the switching circuits 30_1, 30_2,and 30_3.

The reference voltages VREF1, VREF2, and VREF3 applied to the threeswitching circuits 30_1, 30_2, and 30_3 are provided to have a highvoltage as being far away from the position at which the rectifiedvoltage is applied. The light-emitting voltage for the three LEDchannels LED1, LED2, and LED3 rises as being far away from the positionat which the rectified voltage is applied. Therefore, the three currentdetection resistors Rg1, Rg2, and Rg3 of FIG. 8 having the uniformresistance values are applied with the high rectified voltage as beingfar away from the position at which the rectified voltage is applied,and thus may provide the reference voltages of the switching circuits30_1, 30_2, and 30_3 connected thereto and the detection voltage havingthe level meeting the turn on conditions.

The light-emitting operation of the three LED channels LED1, LED2, andLED3 of FIG. 8 will be described.

The three switching circuits 30_1, 30_2, and 30_3 compare the referencevoltages VREF1, VREF2, and VREF3 applied thereto with the levels of thecurrent detection voltage of the current detection resistors Rg1, Rg2,and Rg3 connected thereto to provide the current paths.

The three switching circuits 30_1, 30_2, and 30_3 in the initial statemaintain the turned on state by a difference between the currentdetection voltage formed in the current detection resistors Rg1, Rg2,and Rg3 and the reference voltages VREF1, VREF2, and VREF3 appliedthereto.

However, since the rectified voltage in the initial state does not reachthe light-emitting voltage for light-emitting the LED channel LED1, thelight source 12 does not emit light. Therefore, the current paths arenot formed by the switching circuits 30_1, 30_2, and 30_3.

When the rectified voltage rises to reach the light-emitting voltage forlight-emitting the LED channel LED1, the rectified voltage is applied tothe current detection resistor Rg1 through the current path formed bythe switching circuit 30_1.

That is, the switching circuit 30_1 provides the current pathcorresponding to the case in which the rectified voltage reaches thelight-emitting voltage of the LED channel LED1 and when the current pathis provided by the switching circuit 30_1, the LED channel LED1 islight-emitted.

When the LED channel LED1 is light-emitted and then the rectifiedvoltage rises, the current inflow amount supplied to the currentdetection resistor Rg1 through the switching circuit 30_1 increases. Asa result, the current detection voltage applied to the current detectionresistor Rg1 rises. The current detection voltage applied to the currentdetection resistor Rg1 is not out of the level for maintaining theturned on state of the NMOS transistor 52 before the rectified voltagereaches the light-emitting voltage for light-emitting the LED channelsLED1 and LED2.

Thereafter, when the rectified voltage reaches the light-emittingvoltage for light-emitting the LED channels LED1 and LED2, the turned onswitching circuit 30_2 provides the current path.

In this case, the current detection voltage applied to the negative (−)terminal of the comparator 50 of the switching circuit 30_1 is in astate higher than that of the reference voltage VREF1 due to the risingof the rectified voltage applied to the current detection resistor Rg1.Therefore, the switching circuit 30_1 is turned off not to provide thecurrent path and only the switching circuit 30_2 provides the currentpath for light-emitting the LED channels LED1 and LED2.

As described above, the current path is changed from the switchingcircuit 30_1 to the switching circuit 30_2 in response to the rising ofthe rectified voltage and the LED channels LED1 and LED2 arelight-emitted through the current path changed to the switching circuit30_2.

When the rectified voltage rises, the LED channels LED1, LED2, and LED3are sequentially turned on additionally one by one to the position faraway from the position at which the rectified voltage is applied and thecurrent paths are sequentially shifted to the position far away from theposition at which the rectified voltage is applied.

After all the LED channels LED1, LED2, and LED3 are turned on, therectified voltage falls.

When the rectified voltage starts to fall and then falls to thelight-emitting voltage or less for light-emitting the LED channel LED3,the LED channel LED3 is quenched and the current path is formed by theswitching circuit 30_2.

The LED channels LED3, LED2, and LED1 are sequentially quenched inresponse to the falling of the rectified voltage and the current pathsare sequentially shifted to a close position from the position far awayfrom the position at which the rectified voltage is applied.

Further, the preferred embodiment of the present invention may beperformed by a configuration adopting the uniform reference voltage andthe independent current detection resistors as illustrated in FIG. 9 soas to drive the three LED channels LED1, LED2, and LED3.

The preferred embodiment of FIG. 9 is different from the preferredembodiment of FIG. 8 in terms of the configuration of the referencevoltage generation circuit 20 but the remaining components of thepreferred embodiment of FIG. 9 are the same as those of the preferredembodiment of FIG. 8, and therefore the configuration and operationthereof will not be repeatedly described.

In the configuration of FIG. 9, the reference voltage generation circuit20 is configured to provide a fixed reference voltage Vrefc to eachswitching circuit 30_1, 30_2, and 30_3 and divide the constant voltageVref using resistors Rr1 and Rr2 so as to output the reference voltageVrefc.

By doing so, the three current detection resistors Rg1, Rg2, and Rg3 mayhave a low resistance values as being far away from the position atwhich the rectified voltage is applied so as to satisfy the turn onconditions for each of the switching circuits 30_1, 30_2, and 30_3.

The light-emitting voltages for each LED channels LED1, LED2, and LED3rise as being far away from the position at which the rectified voltageis applied.

Therefore, each current detection resistors Rg1, Rg2, and Rg3 having lowresistance values as being far away from the position at which therectified voltage is applied may be applied with a high light-emittingvoltage as being far away from the position at which the rectifiedvoltage is applied to provide the current detection voltagecorresponding to the fixed reference voltage Vrefc.

The light-emitting operation of the three LED channels LED1, LED2, andLED3 of FIG. 9 will be described.

The three switching circuits 30_1, 30_2, and 30_3 compare the referencevoltage Vrefc with the levels of the current detection voltage of thecurrent detection resistors Rg1, Rg2, and Rg3 connected thereto toprovide the current paths.

The three switching circuits 30_1, 30_2, and 30_3 in the initial statemaintain the turned on state by a difference between the currentdetection voltage formed in the current detection resistors Rg1, Rg2, .. . , Rg3 and the reference voltages Vrefc.

Since the rectified voltage in the initial state does not reach thelight-emitting voltage for light-emitting the LED channel LED1, thelight source 12 does not emit light. Further, the current paths are notalso formed by the switching circuits 30_1, 30_2, and 30_3.

When the rectified voltage rises to reach the light-emitting voltage forlight-emitting the LED channel LED1, the rectified voltage is applied tothe current detection resistor Rg1 through the current path formed bythe switching circuit 30_1.

That is, the switching circuit 30_1 provides the current pathcorresponding to the case in which the rectified voltage reaches thelight-emitting voltage of the LED channel LED1 and when the current pathis provided by the switching circuit 30_1, the LED channel LED1 islight-emitted.

When the rectified voltage is applied to the current detection resistorRg1 through the switching circuit 30_1, the current detection voltage ofthe current detection resistor Rg1 rises to the level of thelight-emitting voltage, and then depends on the variation of therectified voltage.

When the LED channel LED1 is light-emitted and then the rectifiedvoltage rises, the current inflow amount supplied to the currentdetection resistor Rg1 through the switching circuit 30_1 increases. Asa result, the current detection voltage applied to the current detectionresistor Rg1 rises. The detection voltage applied to the currentdetection resistor Rg1 is not out of the level for maintaining theturned on state of the NMOS transistor 52 before the rectified voltagereaches the light-emitting voltage for turning on the LED channels LED1and LED2.

Thereafter, when the rectified voltage reaches the light-emittingvoltage for turning on the LED channels LED1 and LED2, the turned onswitching circuit 30_2 provides the current path.

In this case, the current detection voltage applied to the negative (−)terminal of the comparator 50 of the switching circuit 30_1 is in astate higher than that of the reference voltage Vrefc due to the risingof the rectified voltage. Therefore, the switching circuit 30_1 isturned off not to provide the current path. Therefore, only theswitching circuit provides the current path for light-emitting the LEDchannels LED1 and LED2.

As described above, the current path is changed from the switchingcircuit 30_1 to the switching circuit 30_2 in response to the rising ofthe rectified voltage and the LED channels LED1 and LED2 arelight-emitted through the current path changed to the switching circuit30_2.

Thereafter, when the rectified voltage rises gradually, the currentpaths are sequentially shifted to the position far away from theposition at which the rectified voltage is applied. Therefore, the LEDchannels LED1, LED2, and LED3 are sequentially light-emittedadditionally to the position far away from the position at which therectified voltage is applied.

After all the LED channels LED1, LED2, and LED3 are light-emitted, therectified voltage falls.

When the rectified voltage starts to fall and then falls to thelight-emitting voltage or less for light-emitting the LED channel LED3,the LED channel LED3 is turned off and the current path is formed by theswitching circuit 30_2.

The LED channels LED3, LED2, and LED1 are sequentially quenched inresponse to the falling of the rectified voltage and the current pathsare sequentially shifted to the close position from the position faraway from the position at which the rectified voltage is applied.

The preferred embodiment of FIGS. 8 and 9 as described above does notuse an inductor, a capacitor, and the like as well as applies thedetection voltage in proportion to the input voltage to each channel,thereby securing the optimal power factor and securing the sufficientcurrent regulating characteristics.

Further, the preferred embodiment of the present invention forms thecurrent paths for each LED channel to simplify components configuringthe LED driving circuit, such that the circuit may be implemented tohave a simple structure.

Further, the preferred embodiment of the present invention may beconfigured to perform a current regulation function of allowing thelight source 12 to emit light and a function of compensating for achange in power according to the variation of the rectified voltage, asillustrated in FIG. 10.

To this end, the preferred embodiment of FIG. 10 includes a voltagesensing unit 200 which provides a sensing signal sensing the rectifiedvoltage. Comparing with FIG. 1, components of the preferred embodimentof FIG. 10 is the same as those of the preferred embodiment of FIG. 1other than the voltage sensing unit 200, and therefore the descriptionthereof will not be repeatedly described.

Further, the voltage sensing unit 200 may be configured to include thecurrent control circuit 14. In particular, the voltage sensing unit 200may be integrally configured with the reference voltage generationcircuit 20 or separately configured therefrom. Further, the voltagesensing unit 200 may be configured to be included in the power supplycircuit or separately configured from the current control circuit 14.The configuration of the voltage sensing unit 200 may be variouslydetermined according to the manufacturer's intention.

The voltage sensing unit 200 senses the rectified voltage input as thesame frequency, phase, and waveform as those supplied to the lighting 10and outputs the compensation voltage corresponding to the change in therectified voltage.

The reference voltage generation circuit 20 provides the referencevoltages VREF1, VREF2, and VREF3 varying in response to the compensationsignal to each switching circuit 30_1, 30_2, and 30_3.

As described above, the current amount flowing through the current pathmay be controlled so as to constantly supply power to the light source12 by the operation of the voltage sensing unit 200.

That is, the voltage sensing unit 200 compensates for the instablerectified voltage occurring due to the environmental factors.

The power may be represented by a product of current and voltage.Therefore, the rising or falling of the rectified voltage may becompensated by controlling the current through the current path.

That is, when the current flowing in the light source 12 maintains aconstant level by the compensation voltage of the voltage sensing unit200, the illumination of the light source 12 may be maintainedconstantly.

In more detail, the voltage sensing unit 200 may be configured tocompensate for the variation of the rectified voltage by controlling thecurrent amount through the current path formed in the current controlcircuit 14. More preferably, the compensation voltage output from thevoltage sensing unit 200 may be determined as a level inverselyproportional to the variation value of the rectified voltage.

In more detail, the voltage sensing unit 200 illustrated in FIG. 10 maybe configured to provide the compensation voltage to a node outputtingthe reference voltage having the highest level or a node applied with avoltage higher than the reference voltage having the highest level,among the nodes between the resistors of the reference voltagegeneration circuit 20.

By the above configuration, the compensation voltage output from thevoltage sensing unit 200 may be constantly reflected to the referencevoltages VREF1, VREF2, and VREF3 in response to the resistance ratio ofeach resistor.

When the rectified voltage is low, the voltage sensing unit 200 providesthe compensation voltage to the reference voltage generation circuit 20as the level inversely proportional to the decrease in the rectifiedvoltage.

The reference voltage generation circuit 20 provides the referencevoltages VREF1, VREF2, and VREF3 increasing in response to thecompensation voltage to the positive (+) terminals of each comparator 50of the switching circuit 30_1, 30_2, and 30_3.

The comparator may provide the voltage having the increasing level tothe gate of the NMOS transistor 52 in response to the rising of thevoltage level of the positive (+) terminal. As a result, the currentdriving ability of the NMOS transistor 52 increases and the currentamount through the current path in response to the light-emitting of thelight source 12 increases.

The increase in the current amount flowing in the NMOS transistor 52means the increase in the current amount supplied to the light source12. Therefore, the power for allowing the light source 12 to emit lightmay be maintained constantly, such that the illumination may bemaintained constantly.

To the contrary, even when the rectified voltage rises, the voltagesensing unit 200 provides the compensation voltage to the referencevoltage generation circuit 20 as the level inversely proportional to therising of the rectified voltage.

The reference voltage generation circuit 20 provides the referencevoltages VREF1, VREF2, and VREF3 falling in response to the compensationvoltage to the positive (+) terminals of each comparator 50 of theswitching circuit 30_1, 30_2, and 30_3.

The comparator may provide the voltage having the falling level to thegate of the NMOS transistor 52 in response to the falling of the voltagelevel of the positive (+) terminal. As a result, the current drivingability of the NMOS transistor 52 decreases and the current amountthrough the current path in response to the light-emitting of the lightsource 12 decreases.

The decrease in the current amount flowing in the NMOS transistor 52means the decrease in the current amount supplied to the light source12. Therefore, the power for allowing the light source 12 to emit lightmay be maintained constantly, such that the illumination may bemaintained constantly.

That is, even thought the rectified voltage varies due to theenvironmental factors, the present invention compensates for therectified voltage as described above, such that the power supplied tothe light source 12 may be maintained constantly.

Therefore, according to the preferred embodiment of the presentinvention, the variation of the rectified voltage occurring due to theenvironmental factors is compensated, such that the power supplied tothe light source to emit light may be compensated and the light sourcemay maintain the illumination constantly. Therefore, the reliability ofa product may be improved.

FIG. 10 illustrates that the voltage sensing unit 200 is applied to thepreferred embodiment of FIG. 1, but the preferred embodiment of thepresent invention may be configured as illustrated in FIG. 11 that thevoltage sensing unit 200 is applied to the preferred embodiment of FIG.8 according to the manufacturer's intention or the preferred embodimentof the present invention may be configured as illustrated in FIG. 12that the voltage sensing unit 200 is applied to the preferred embodimentof FIG. 9.

The preferred embodiments of FIGS. 11 and 12 may compensate for thepower of the light source 12 in response to the variation of therectified voltage similarly to the operation by the compensation voltageof the voltage sensing unit 200 of FIG. 10, and therefore thedescription thereof will not be repeatedly described.

As is apparent from the above description, the present inventionprovides a lighting apparatus which can obtain the improved power factorby excluding the inductor, the capacitor, and the like, and obtain theimproved power factor and current regulation characteristics by applyingthe current detection voltage in proportion to the rectified voltage tothe current paths for each channel.

Further, the present invention provides components configuring the LEDdriving circuit which can be simplified by allowing the common currentdetection resistor to define the current detection voltage varying inresponse to the rectified voltages for each LED channel, such that theLED driving circuit can be configured to have the simple structure.

In addition, the present invention provides an improved method ofarranging the LED channels on the region of the substrate, such that theheat radiating efficiency and the illumination of the LED lightingapparatus can be improved.

Also, the present invention compensates for building or local ornational power supply environment factors or temporarily unstable powersupply environment factors by controlling current to compensate for thepower for light-emitting the lighting which is light-emitted by drivingthe LEDs.

Moreover, the present invention compensates for the power forlight-emitting the lighting to allow the LED lighting apparatus to belight-emitted with the uniform illumination in various powerenvironments, thereby maximizing the reliability of a product.

Although a preferred embodiment of the present invention has beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and the spirit of theinvention as disclosed in the accompanying claims.

What is claimed is:
 1. An LED lighting apparatus comprising: a powersupply unit configured to convert an AC voltage and provide a rectifiedvoltage; a light source configured to include N light emitting diode(LED) channels (N is a natural number) including at least one LED; and acurrent control circuit configured to divide a varying width of therectified voltage into N periods in response to light-emitting voltagesfor each LED channel, detect current flowing in the LED channelscorresponding to the period, generate a plurality of reference voltageshaving different levels corresponding to the LED channels, reflect avariation of the rectified voltage to the plurality of the referencevoltages, and control the light source to emit light by controllingamount of the current flowing in the LED channels by comparing a currentdetection voltage corresponding to the detected current with a referencevoltage reflecting the variation of the rectified voltage.
 2. The LEDlighting apparatus of claim 1, wherein the current control circuitcomprises: N switching circuits each configured to correspond to eachLED channel and be connected to each LED channel in parallel to formcurrent paths; a current detection resistor configured to be commonlyconnected between the N switching circuits and a ground to provide thecurrent detection voltage; and a voltage sensing unit configured tosense the variation of the rectified voltage to provide a compensationvoltage; and a reference voltage generation circuit configured toprovide the plurality of the reference voltages having the differentlevels corresponding to each switching circuit and reflecting thecompensation voltage, wherein the N switching circuits compare thereference voltage corresponding thereto with the current detectionvoltage to selectively provide the current paths.
 3. The LED lightingapparatus of claim 2, wherein the voltage sensing unit provides thecompensation voltage as a level inversely proportional to a variationvalue of the rectified voltage.
 4. The LED lighting apparatus of claim2, wherein the voltage sensing unit is configured to apply thecompensation voltage to any one of a node outputting a highest referencevoltage or a node applied with a voltage having a level higher than thatof the highest reference voltage, among the nodes outputting theplurality of reference voltages of the resistors of the referencevoltage generation circuit.
 5. The LED lighting apparatus of claim 2,wherein the reference voltage generation circuit provides the referencevoltage to the switching circuit connected to the LED channel having ahigh light-emitting voltage and provides the reference voltage to theswitching circuit connected to the LED channel having a lowlight-emitting voltage.
 6. The LED lighting apparatus of claim 2,wherein the N switching circuits gradually shift a position of thecurrent path to the LED channel having the high light-emitting voltagewhen the rectified voltage rises and gradually shift a position of thecurrent path to the LED channel having the low light-emitting voltagewhen the rectified voltage falls.
 7. The LED lighting apparatus of claim2, wherein the N switching circuits comprise: a comparator configured tocompare the reference voltage with the current detection voltage tooutput the compared results; and a switching element configured to turnon/off the current path between the LED channel connected thereto andthe current detection resistor in response to an output of thecomparator.
 8. The LED lighting apparatus of claim 1, wherein thecurrent control circuit comprises: N switching circuits each configuredto correspond to each LED channel and connected to each LED channel inparallel to form current paths; N current detection resistors configuredto be independently connected between the N switching circuits and aground to provide the current detection voltage; a voltage sensing unitconfigured to sense the variation of the rectified voltage to provide acompensation voltage; and a reference voltage generation circuitconfigured to provide the plurality of reference voltages correspondingto each switching circuit and reflecting the compensation voltage, andthe N switching circuits compare the reference voltage correspondingthereto with the current detection voltage to selectively provide thecurrent paths.
 9. The LED lighting apparatus of claim 8, wherein the Ncurrent detection resistors have uniform resistance values so as tosatisfy turn on conditions for each of the N switching circuits.
 10. TheLED lighting apparatus of claim 8, wherein the voltage sensing unitprovides the compensation voltage as a level inversely proportional tothe variation value of the rectified voltage.
 11. The LED lightingapparatus of claim 8, wherein the voltage sensing unit is configured toapply the compensation voltage to any one of a node outputting a highestreference voltage or a node applied with a voltage having a level higherthan that of the highest reference voltage, among the nodes outputtingthe plurality of reference voltages of the resistors of the referencevoltage generation circuit.